My first Coreflute project

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My first Coreflute project

Postby raptordesigns » Sat Jun 27, 2009 5:20 pm

It's not anywhere near finished yet, needs a tailbox and work on the bottom section plus general cleanup, but it's getting there...

It looks like a bullet.
Image

There's a hinge up front
Image

The bottom bit isn't done yet.
Image

Here's the bones of the thing.
Image

I've ridden it briefly as it is. It's already faster. Minor adjustments required, my knees brush the top panel at present.
Last edited by raptordesigns on Sat Jul 04, 2009 5:03 pm, edited 2 times in total.
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by BNA » Sun Jun 28, 2009 5:20 pm

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Re: My first Coreflute project

Postby bradwoodbr » Sun Jun 28, 2009 5:20 pm

A fantastic result so far, especially if it is already faster.
How did you make up the front hinge?
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Re: My first Coreflute project

Postby raptordesigns » Sun Jun 28, 2009 5:52 pm

bradwoodbr wrote:A fantastic result so far, especially if it is already faster.
How did you make up the front hinge?


Fortunately I took a photo at that stage!

The bottom bracket has an extension that allows me to slide another tube into it. The latter tube is part of the fairing and has a hinge as you can see in the photo below (in the folded-down position). The hinge provides a limit stop so that the fairing comes down to the correct angle.

The black rubber tube "bungee" you can see in the photo tied between front and rear of the hinge was only temporary and is not required in the final version as the weight of the rear of the fairing keeps it in position nicely.

Image

As for faster - I took it down to the local velodrome. My subjective feeling was that I gained at least an extra 5km/hr for the same effort at "cruise". Maintaining a constant 40km/hr was no effort. (my normal average "easy" training speed for an hours' pedalling around the drome is usually between 33-35km/hr)

I figured that wasn't bad given that the back was wide open - and quite wide, the bottom wasn't done at all (bottom front quite dirty) and my knees were not clearing the top panel so I had to hold up the fairing slightly with my knuckles all the time.

John R.
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Re: My first Coreflute project

Postby bradwoodbr » Sun Jun 28, 2009 11:12 pm

That hinge idea is very ingeneuos John. Especailly being able to insert tubing on the front side of the BB.
Thanks for sharing and I look forward to the final product. :)

Cheers
Brad
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Re: My first Coreflute project

Postby Poiter » Mon Jun 29, 2009 10:38 pm

The grass needs a mow..
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Re: My first Coreflute project

Postby Freddyflatfoot » Wed Jul 01, 2009 8:46 am

Priorities Poit! priorities...........................
Cheers!
Rob
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Re: My first Coreflute project

Postby raptordesigns » Sat Jul 04, 2009 2:05 pm

Freddyflatfoot wrote:Priorities Poit! priorities...........................


The grass can definitely wait... it's almost finished!
Image

The tail box has a floor that extends just forward of my seat. There's a hole in the floor between here and just behind the bottom bracket so that I can put my feet down. There doesn't appear to be any breeze coming in through the hole - but if I put my hand down thru it I can certainly feel one just below....

This is a "yes-there-are-compromises" fairing - not designed to be much good for the street, but nevertheless able to be managed by the rider without needing a team to seal me in and get me out.

Image

Too windy to do any pace - the crosswind section of the velodrome started getting scary once I hit 40km/hr.

Shots from a video.
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Re: My first Coreflute project

Postby Freddyflatfoot » Sat Jul 04, 2009 5:31 pm

I like the look of that velodrome John! Much gentler than the one here in Ballarat, the sides on that one are viscious, and the boundary between the apron and the banked sides is quite sudden.
The fairing looks good! More piccies of the finished product!
Did I say I should get cracking on a velo body for my trike? But then I'm also working on my FWD project..............................
Not enough hours in the day!
Cheers!
Rob
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Re: My first Coreflute project

Postby raptordesigns » Sun Jul 05, 2009 11:51 am

Freddyflatfoot wrote:I like the look of that velodrome John! Much gentler than the one here in Ballarat, the sides on that one are viscious, and the boundary between the apron and the banked sides is quite sudden.

Carnegie is a nice track with a good, smooth surface. It's a 360m track, so you don't need a huge bank. The downside is that it is often very windy with strong sea breezes most afternoons from mid-spring to mid-autumn. Also the Carnegie Cycling Club has it reserved for much of the best times.
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Re: My first Coreflute project

Postby bradwoodbr » Sun Jul 05, 2009 3:20 pm

raptordesigns wrote: This is a "yes-there-are-compromises" fairing - not designed to be much good for the street, but nevertheless able to be managed by the rider without needing a team to seal me in and get me out.

Too windy to do any pace - the crosswind section of the velodrome started getting scary once I hit 40km/hr.


What do you mean by "not much good for the street"? I thought your inventive front hinge and open bottom section would make it very street friendly.
Is it because of the effect of sidewinds?
Can a rounded design provide better manners at speed in sidewinds? (Just thinking out loud).

I think your finised full fairing looks really compact, streamlined and functional.
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Re: My first Coreflute project

Postby raptordesigns » Sun Jul 05, 2009 9:44 pm

bradwoodbr wrote:What do you mean by "not much good for the street"? I thought your inventive front hinge and open bottom section would make it very street friendly.
Is it because of the effect of sidewinds?
Can a rounded design provide better manners at speed in sidewinds? (Just thinking out loud).


I doubt I'd ever use it as a commuter - I much prefer my somewhat higher SWB bike for that, even compared with the lowracer without fairing. But I did take it on a 30km jaunt from home to St Kilda and back today along Beach Rd for the monthly "come-'n-try" day, and it was OK - except that we had a 30km/hr crosswind blowing off the bay and every time I passed a gap in trees or a cross street that let the wind blow across the road, it got scary. I didn't get passed by any roadies (I passed a lot though), but because of the cross-wind, once again wasn't able to try for any speed greater than about 40.

I fitted a rear view mirror but discovered that I really need some turn signals - and maybe brake lights too! I can't get my arms out of the box. People can't tell whether I'm pedaling or not either.

I doubt a more rounded shape would help much with the crosswind issue. There's just too much area forward of the front wheel.

Oh, an afterthought edit here: It maxxed out at only 13 degrees today. It was like a sauna in the shell when I was working hard up the hills. There's very little airflow at all inside the thing. I got out soaked with sweat.
Last edited by raptordesigns on Sun Jul 05, 2009 10:01 pm, edited 1 time in total.
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Re: My first Coreflute project

Postby Freddyflatfoot » Sun Jul 05, 2009 10:00 pm

Interesting that you found the 30? kph crosswinds scary. That would be a relatively low wind speed up my neck of the woods!
I find with my SWB with tailbox and wheel disc doesn't really get hairy, until the crosswinds are at least 50 kph. Anything around 65 and it gets really interesting!
Wonder how a velo copes in strong crosswinds? You would think a trike would be less affected.
Once I finish my FWD, maybe i'd better build a body and find out!
Cheers!
Rob
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Re: My first Coreflute project

Postby raptordesigns » Sun Jul 05, 2009 10:03 pm

Freddyflatfoot wrote:Interesting that you found the 30? kph crosswinds scary. That would be a relatively low wind speed up my neck of the woods!
I find with my SWB with tailbox and wheel disc doesn't really get hairy, until the crosswinds are at least 50 kph. Anything around 65 and it gets really interesting!
Wonder how a velo copes in strong crosswinds? You would think a trike would be less affected.
Once I finish my FWD, maybe i'd better build a body and find out!


I have the same experience - the tail box and rear wheel disk never gave me any problem even in really strong crosswinds. A try at a front wheel disk though, was very different. That sucker came off after the first windy day.
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Re: My first Coreflute project

Postby raptordesigns » Mon Jul 06, 2009 9:42 am

For your enjoyment - the video of the first velo lap.

http://www.youtube.com/watch?v=ItXrlWPlcLo
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Re: My first Coreflute project

Postby Storm » Fri Jul 10, 2009 8:27 am

Thanks for posting the vid it looks quite smooth, a great perspective with the other two cycling along with you. :D
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Re: My first Coreflute project

Postby raptordesigns » Sun Jul 12, 2009 4:30 pm

Storm wrote:Thanks for posting the vid it looks quite smooth, a great perspective with the other two cycling along with you. :D


And for a different perspective....

Image

My excuse is that it's too windy to ride.
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Re: My first Coreflute project

Postby raptordesigns » Wed Jul 15, 2009 4:01 pm

OK, I'm officially a wimp, I think.

I managed to get the beast down to the Edithvale velodrome at lunchtime and took it for a spin in no-wind conditions.

No problem tooling along at 30km/hr - hardly even pushing the pedals.

40km/hr: about the same effort I'd normally put in at 30 (my normal commuting speed with no fairing).

45km/hr, easy to maintain without much strain.

50km/hr and I'm doing multiple laps at this speed, accelerating down the straights but getting worried on the turns and backing off....

Apart from a few discrete unfaired laps at DISC (which has a 42 degree bank), I don't think I've ever done turns at anywhere near 50km/hr before and I found it a bit intimidating. I need to get some practice and assure myself that I can bank it in on this lower slope and not go skittering off the edge before I will be willing to wind up the speed above 50 on the velodrome. I need to find a straight, smooth road with no lights!

John R.
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Re: My first Coreflute project

Postby bradwoodbr » Thu Jul 16, 2009 2:04 am

Go for it mate! What a thrill!
Remember you've got a fairing around you to protect you if the rubber goes sunny side up. :)
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Re: My first Coreflute project

Postby raptordesigns » Thu Jul 16, 2009 7:09 am

It's fun, but it would be nice to put a real rider in the thing. Here's a bit of perspective:

I was listening to the Tour de France pre-coverage last night and they mentioned the wattage data recorded from one of the riders.

At one stage the rider was doing 61km/hr in the peleton (ie: drafting) on the flat. His output was 583 watts. He later was recorded on the flat at the same speed, but as the lead rider, and he was pumping 800 watts. In the sprint, he was measured at 1323 watts.

(Note: 61km/hr isn't a speed they maintain for very long - the average speed of the peleton on the flat seems to be in the 45km/hr range - but they keep it up for hours!)

The solo (non-drafting, 800 watts) power/speed actually corresponds well with the calculator at http://www.noping.net/english/

According to the same calculator, if the rider had been in a lowracer, unfaired, they would have been doing 70km/hr, in a lowracer with a tailbox, 74km/hr, and in a streamlined trike, 86km/hr. In a proper streamlined speed bike: 113km/hr

My guess is that my fairing would be slightly better than a tail box, so that same rider could achieve something in the region of 80km/hr in my beast at 800 watts, and a frightening 95km/hr at 1320 watts

It's been fun experimenting, but a fairing like this will never make a speed demon out of an ageing non-athlete like me!!!
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Re: My first Coreflute project

Postby Freddyflatfoot » Thu Jul 16, 2009 10:19 am

Wow! Good figures John.
I just puched in some of my figures, and confirmed what I had suspected.
I don't work very hard, putting out maybe 120-150 watts on my normal rides, with maybe 200 on a climb!
Also played around with bike weights. Amazing! Going from 18 kg down to 12 kg hardly made any difference on the flat.
Thanks for the link, I'll have to play with that calculator some more!
So, are you going to be really quick around the lake next year?
Cheers!
Rob
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Re: My first Coreflute project

Postby raptordesigns » Thu Jul 16, 2009 11:42 am

Freddyflatfoot wrote:Wow! Good figures John.
I just punched in some of my figures, and confirmed what I had suspected.
I don't work very hard, putting out maybe 120-150 watts on my normal rides, with maybe 200 on a climb!
Also played around with bike weights. Amazing! Going from 18 kg down to 12 kg hardly made any difference on the flat.
Thanks for the link, I'll have to play with that calculator some more!
So, are you going to be really quick around the lake next year?


Yes, if you punch in the numbers for your own rides, it's a humbling experience. Those TDF guys are just awesome compared with we mere mortals.

You really wouldn't expect much if any difference on the flat by bicycle weight. The weight only has any major bearing on speed on the flat when there's acceleration and deceleration happening. More weight means more inertia, so it takes more work to get up to speed. My take is that once you're at a specific speed, the only extra load more weight puts on you is due to extra rolling resistance (friction in the bearings and the tyre contact patch). It's small though.

As for the lake: well, if we do it - and I'm trained up - and in the fish - and if it's not too windy, then I can't see many of those Sebasopol brats overtaking in a hurry! :-) We still have to figure out how to stop them cheating though.
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